With the addition of inductive poloidal current drive for current profile control in the Madison Symmetric Torus (MST) reversed field pinch, the magnetic fluctuation amplitude halves, leading to reduced energy and particle transport. A four- to five-fold increase in the energy confinement time to ${\tau }_E\sim 5\mathrm{ms}$ with both decreased Ohmic input power and increased stored thermal energy coincides with record low fluctuation amplitude and record high electron temperature $\sim 600\mathrm{eV}$ (for MST). $\beta [=2\mathrm{}{\mu }_o〈p〉/B(a{)}^2]$ increases from 6% to 8%. Other improvements include reduced electrostatic edge turbulence and plasma impurity content.

• Received 8 October 1996

DOI:https://doi.org/10.1103/PhysRevLett.78.62